In paper making industry, cationic starch has widely been used by including the same in pulp at the time of paper making thereof as dry strength agent, retention aid, drainage aid, printability improver and the like. Furthermore such cationic starch has variously been utilized as warp sizing agent and finish in textile industry, besides as flocculant, emulsifier and the like in other industries.
As the process for producing cationic starch as described above, generally practiced is such a process which comprises either reacting pasty or slurry starch with an alkylamine halide such as diethylaminoethyl chloride or an aminochlorohydrin compound such as 3-chloro-2-hydroxypropyltrimethylammonium chloride, or with a glycidylamine such as 2, 3-epoxypropyltrimethylammonium chloride in the presence of strong alkali as described in Starch: Chemistry and Technology, vol II, 1967, pp. 403-420, Academic Press Co.